title: Stress induces plant somatic cells to acquire some features of stem cells accompanied by selective chromatin reorganization.
abstract: BACKGROUND
  Previous data suggested that senescing cells or cells exposed to acute stress may acquire stem cell properties characterized by open chromatin conformation and by promiscuous expression of transcription factor genes. To further explore the link between stress response and dedifferentiation, we generated transgenic plants in which a reporter AtMBD6-GFP is controlled by a meristem-specific promoter derived from the ANAC2 gene together with the analysis of chromatin conformation.
  
  
  RESULTS
  We found that ANAC2 promoter is essentially active in the shoot and the root apical meristems including leaf primordia. ANAC2 was activated in mature leaves following exposure to various stress conditions including protoplasting and dark. This activity was associated with decondensation of pericentric but not of centromeric chromatin. Using epigenetic mutants, ddm1 and kyp/suvh4, we found that compaction at centromeric chromatin persists despite a significant reduction in DNA and histone methylation.
  
  
  CONCLUSIONS
  Our results suggest that extreme environmental signals trigger plant somatic cells to acquire stem cell properties before assuming a new cell fate. Results also pointed to distinct mechanisms involved in controlling chromatin compaction at chromocenter and that compaction of centromeric chromatin may not be dependent on epigenetic means driven by DDM1 and KYP/SUVH4 chromatin modifier proteins.
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
authors.forename: Assa
authors.initials: A
authors.lastname: Florentin
authors.forename: Meytal
authors.initials: M
authors.lastname: Damri
authors.forename: Gideon
authors.initials: G
authors.lastname: Grafi
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000378:metabolism; D059828:Plant Cells / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000502:physiology; D015398:Signal Transduction; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C118957:DDM1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D011495:Histone-Lysine N-Methyltransferase; C471228:SUVH4 protein, Arabidopsis
keywords: Arabidopsis; DNA methylation; chromatin reorganization; dedifferentiation; histone modifications; stress response